Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755055AbbLQH7j (ORCPT ); Thu, 17 Dec 2015 02:59:39 -0500 Received: from mx2.suse.de ([195.135.220.15]:48202 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753814AbbLQH7d (ORCPT ); Thu, 17 Dec 2015 02:59:33 -0500 From: Hannes Reinecke To: Bjorn Helgaas Cc: Alexander Duyck , Michal Kubecek , "Shane M. Seymour" , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Hannes Reinecke , Bjorn Helgaas Subject: [PATCH 2/2] pci: Update VPD size with correct length Date: Thu, 17 Dec 2015 08:59:29 +0100 Message-Id: <1450339169-52542-3-git-send-email-hare@suse.de> X-Mailer: git-send-email 1.8.5.6 In-Reply-To: <1450339169-52542-1-git-send-email-hare@suse.de> References: <1450339169-52542-1-git-send-email-hare@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3147 Lines: 101 PCI-2.2 VPD entries have a maximum size of 32k, but might actually be smaller than that. To figure out the actual size one has to read the VPD area until the 'end marker' is reached. Trying to read VPD data beyond that marker results in 'interesting' effects, from simple read errors to crashing the card. And to make matters worse not every PCI card implements this properly, leaving us with no 'end' marker or even completely invalid data. This path modifies the size of the VPD attribute to the available size, and disables the VPD attribute altogether if no valid data could be read. Cc: Alexander Duyck Cc: Bjorn Helgaas Signed-off-by: Hannes Reinecke --- drivers/pci/access.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/drivers/pci/access.c b/drivers/pci/access.c index 59ac36f..0a647b1 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -475,6 +475,56 @@ static const struct pci_vpd_ops pci_vpd_f0_ops = { .release = pci_vpd_pci22_release, }; +/** + * pci_vpd_size - determine actual size of Vital Product Data + * @dev: pci device struct + * @old_size: current assumed size, also maximum allowed size + * + */ +static size_t +pci_vpd_pci22_size(struct pci_dev *dev) +{ + size_t off = 0; + unsigned char header[1+2]; /* 1 byte tag, 2 bytes length */ + + while (off < PCI_VPD_PCI22_SIZE && + pci_read_vpd(dev, off, 1, header) == 1) { + unsigned char tag; + + if (header[0] & PCI_VPD_LRDT) { + /* Large Resource Data Type Tag */ + tag = pci_vpd_lrdt_tag(header); + /* Only read length from known tag items */ + if ((tag == PCI_VPD_LTIN_ID_STRING) || + (tag == PCI_VPD_LTIN_RO_DATA) || + (tag == PCI_VPD_LTIN_RW_DATA)) { + if (pci_read_vpd(dev, off+1, 2, + &header[1]) != 2) + return off + 1; + off += PCI_VPD_LRDT_TAG_SIZE + + pci_vpd_lrdt_size(header); + } + } else { + /* Short Resource Data Type Tag */ + off += PCI_VPD_SRDT_TAG_SIZE + + pci_vpd_srdt_size(header); + tag = pci_vpd_srdt_tag(header); + } + if (tag == PCI_VPD_STIN_END) /* End tag descriptor */ + return off; + if ((tag != PCI_VPD_LTIN_ID_STRING) && + (tag != PCI_VPD_LTIN_RO_DATA) && + (tag != PCI_VPD_LTIN_RW_DATA)) { + dev_dbg(&dev->dev, + "invalid %s vpd tag %02x at offset %zu.", + (header[0] & PCI_VPD_LRDT) ? "large" : "short", + tag, off); + break; + } + } + return 0; +} + int pci_vpd_pci22_init(struct pci_dev *dev) { struct pci_vpd_pci22 *vpd; @@ -497,6 +547,13 @@ int pci_vpd_pci22_init(struct pci_dev *dev) vpd->cap = cap; vpd->busy = false; dev->vpd = &vpd->base; + vpd->base.len = pci_vpd_pci22_size(dev); + if (vpd->base.len == 0) { + dev_dbg(&dev->dev, "Disabling VPD access."); + dev->vpd = NULL; + kfree(vpd); + return -ENXIO; + } return 0; } -- 1.8.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/